An American physicist solved the paradox of Schrödinger's cat. "Schrodinger's Cat"

In 1935, an ardent opponent of the newly emerging quantum mechanics, Eric Schrödinger, published an article that purported to expose and prove the inconsistency new branch development of physics.

The essence of the article is carrying out thought experiment :

A live cat is placed in a completely sealed box.
A Geiger counter containing one radioactive atom is placed next to the cat.
A flask filled with acid is connected directly to the Geiger counter.
The possible decay of a radioactive atom will activate the Geiger counter, which, in turn, will break the flask and the acid spilled from it will kill the cat.
Will the cat stay alive or die if it stays with such inconvenient neighbors?
One hour is allocated for the experiment.

The answer to this question and was called upon to prove the inconsistency quantum theory, which is based on superposition: the law of paradox - all microparticles of our world are always simultaneously in two states, until they begin to be observed.

That is, being in a closed space (quantum theory), our cat, like his unpredictable neighbor - the atom, are simultaneously present in two states:

A living and at the same time dead cat.
A decayed and at the same time not decayed atom.

Which, according to classical physics, is complete absurdity. The simultaneous existence of such mutually exclusive things is impossible.

And this is correct, but only from the point of view of the macrocosm. Whereas in the microworld completely different laws apply, and therefore Schrödinger was mistaken when applying the laws of the macroworld to relations within the microworld. Not understanding that purposeful observation of the ongoing uncertainties of the microworld eliminates the latter.

In other words, if you open closed system, in which a cat is placed along with a radioactive atom, we will see only one of the possible states of the subject.

This was proven by the American physicist from the University of Arkansas, Art Hobson. According to his theory, if you connect a microsystem (radioactive atom) with a macrosystem (Geiger counter), the latter will necessarily become imbued with the state of quantum entanglement of the former and go into superposition. And, since we cannot make a direct observation of this phenomenon, it will become unacceptable for us (as Schrödinger proved).

So, we found out that the atom and the radiation counter are in the same superposition. Then who or what, for this system, can we call a cat? If we think logically, the cat, in this case, becomes an indicator of the state of the radioactive nucleus (simply an indicator):

The cat is alive, the core has not decayed.
The cat is dead, the core has disintegrated.

However, we must take into account the fact that the cat is also part of a single system, since it is also inside the box. Therefore, according to quantum theory, the cat is in a so-called non-local connection with the atom, i.e. in a confused state, which means in a superposition of the microworld.

It follows from this that if there is a sudden change in one of the objects of the system, the same will happen to another object, no matter how far they are from each other. An instantaneous change in the state of both objects proves that we are dealing with a single system, simply divided by space into two parts.

This means that we can say with confidence that Schrödinger’s cat is immediately either alive, if the atom has not decayed, or dead, if the atom has decayed.

And yet, it was thanks to Schrödinger’s thought experiment that a mathematical device was constructed that describes the superpositions of the microworld. This knowledge has found wide application in cryptography and computer technology.

Finally, I would like to note the inexhaustible love for the mysterious paradox of “Schrodinger’s cat” on the part of all kinds of writers and cinema. That's just some examples:

A magical device called “Schrodinger’s Cat” in Lukyanenko’s novel “The Last Watch”.
In Douglas Adams's detective novel, Dirk Gently's Detective Agency, there is a lively discussion of the problem of Schrödinger's cat.
In R. E. Heinlein's novel The Cat Walks Through Walls, main character, a cat, is almost constantly in two states simultaneously.
Lewis Carroll's famous Cheshire cat in the novel "Alice in Wonderland" loves to appear in several places at once.
In the novel Fahrenheit 451, Ray Bradbury raises the issue of Schrödinger's cat, in the form of a living-dead mechanical dog.
In the novel “The Healing Magician,” Christopher Stasheff describes his vision of Schrödinger’s cat in a very original way.

And many other enchanting, completely impossible ideas about such a mysterious thought experiment.

Despite the fact that the planetary model of the atom has proven its validity, the theory existing at that time could not fully explain all processes, which were observed in real life. It turned out that in reality, for some reason, classical Newtonian mechanics does not work at the micro level. Those. the prototype model, borrowed from real life, does not correspond to the observations of scientists of that time in the case of considering the atom instead of our solar system.

Based on this, the concept was significantly redesigned. Such a discipline has emerged as quantum mechanics. The origins of this direction were the outstanding physicist Erwin Schrödinger.

Concept of superposition

The main principle that distinguishes the new theory is superposition principle. According to this principle, a quantum (electron, photon or proton) can be in two states at the same time. If make it easier to understand this formulation, we get a fact that is completely impossible to imagine in our minds. A quantum can be in two places at the same time.

At the time of its appearance, this theory contradicted not only classical mechanics, but also common sense. Even now, an educated person far from physics can hardly imagine such a situation. After all, this understanding ultimately implies that he himself the reader can be here and there now. This is exactly how a person tries to imagine the transition from the macroworld to the microworld.

For a person who was accustomed to experiencing the action of Newtonian mechanics and perceiving himself at one point in space, it was extremely difficult to imagine being in two places at once. Besides, there was no theory or patterns as such during the transition from macro to micro. There was no understanding of specific numerical values and rules.

However, the instruments of that time made it possible to clearly record this “quantum dissonance”. Laboratory instruments confirmed that the formulated postulates are indeed consistent and the quantum is capable of being in two states. For example, electron gas around the nucleus of an atom was detected.

Based on this, Schrödinger formulated a famous concept that is now known as the cat theory. The purpose of this formulation was to show that in classical theory physics formed huge failure, requiring additional study.

Schrödinger's cat

The thought experiment about the cat was that the cat was placed in a closed steel box. The box was equipped a device with a poisonous gas and a device with an atomic nucleus.

Based on known postulates, the nucleus of an atom may disintegrate into components within one hour, but may not disintegrate. Accordingly, the probability of this event is 50%.

If the nucleus decays, then the counter-recorder is triggered, and in response to this event, a toxic substance is released from the previously described device with which the box is equipped. Those. the cat dies from poison. If this does not happen, the cat does not die accordingly. Based on a 50% chance of decay, the cat has a 50% chance of surviving.

Based on quantum theory, an atom can be in two states at once. Those. the atom both decayed and did not decay. This means that the recorder worked, breaking the container with poison, and did not disintegrate. The cat was poisoned by poison, and the cat was not poisoned by poison at the same time.

But it is simply impossible to imagine such a picture that upon opening the box, the researcher discovered both a dead and a living cat. The cat is either alive or dead. This is the paradox of the situation. It is impossible for the viewer's consciousness to imagine a dead-alive cat.

The paradox is that the cat is an object of the macrocosm. Accordingly, to say about him that he is alive and dead, i.e. is in two states at once, similar to a quantum, will not be entirely correct.

Using this example, Schrödinger focused specifically on the fact that there are no clear parallels between the macro- and microworlds. Subsequent comments given by experts explain that a radiation detector-cat system should be considered, not a cat-spectator system. In a detector-cat system, only one event is likely.

"Anyone who isn't shocked by quantum theory, does not understand it,” said Niels Bohr, the founder of quantum theory.
The basis of classical physics is the unambiguous programming of the world, otherwise Laplacean determinism, with the advent of quantum mechanics it was replaced by the invasion of a world of uncertainties and probabilistic events. And here thought experiments came in handy for theoretical physicists. These were touchstones on which new ideas were tested.

"Schrodinger's Cat" is a thought experiment, proposed by Erwin Schrödinger, with whom he wanted to show the incompleteness of quantum mechanics in the transition from subatomic systems to macroscopic systems.

A cat is placed in a closed box. The box contains a mechanism containing a radioactive core and a container of poisonous gas. The probability that the nucleus will decay in 1 hour is 1/2. If the nucleus disintegrates, it activates the mechanism, it opens a container of gas, and the cat dies. According to quantum mechanics, if no observation is made of the nucleus, then its state is described by a superposition (mixing) of two states - a decayed nucleus and an undecayed nucleus, therefore, a cat sitting in a box is both alive and dead at the same time. If the box is opened, then the experimenter can see only one specific state - “the nucleus has decayed, the cat is dead” or “the nucleus has not decayed, the cat is alive.”

When does the system cease to exist? How does one mix two states and choose one specific one?

Purpose of the experiment- show that quantum mechanics is incomplete without some rules indicating under what conditions the wave function collapses (an instantaneous change in the quantum state of an object that occurs when measured), and the cat either becomes dead or remains alive, but ceases to be a mixture of both.

Since it is clear that a cat must be either alive or dead (there is no state intermediate between life and death), this means that this is also true for the atomic nucleus. It will necessarily be either decayed or undecayed.

Schrödinger's article "The Current Situation in Quantum Mechanics" presenting a thought experiment with a cat was published in the German journal " Natural sciences” in 1935 to discuss the EPR paradox.

The papers by Einstein-Podolsky-Rosen and Schrödinger outlined the strange nature of “quantum entanglement” (a term coined by Schrödinger), characteristic of quantum states that are a superposition of the states of two systems (for example, two subatomic particles).

Interpretations of quantum mechanics

During the existence of quantum mechanics, scientists have put forward different interpretations of it, but the most supported of all today are the “Copenhagen” and “many-worlds” ones.

"Copenhagen Interpretation"- this interpretation of quantum mechanics was formulated by Niels Bohr and Werner Heisenberg during their joint work in Copenhagen (1927). Scientists have tried to answer questions arising from the wave-particle duality inherent in quantum mechanics, in particular the question of measurement.

In the Copenhagen interpretation, the system ceases to be a mixture of states and chooses one of them at the moment when the observation occurs. The experiment with the cat shows that in this interpretation the nature of this very observation - measurement - is not sufficiently defined. Some believe that experience suggests that as long as the box is closed, the system is in both states simultaneously, in a superposition of the states “decayed nucleus, dead cat” and “undecayed nucleus, living cat,” and when the box is opened, then only then does the wave function collapse to one of the options. Others guess that the "observation" occurs when a particle from the nucleus hits the detector; however (and this key point thought experiment) in the Copenhagen interpretation there is no clear rule that says when this happens, and therefore this interpretation is incomplete until such a rule is introduced into it, or is told how it can be introduced. The exact rule is that randomness appears at the point where the classical approximation is first used.

Thus, we can rely on the following approach: in macroscopic systems we do not observe quantum phenomena (except for the phenomenon of superfluidity and superconductivity); therefore, if we impose a macroscopic wave function on a quantum state, we must conclude from experience that the superposition breaks down. And although it is not entirely clear what it means for something to be “macroscopic” in general, what is certain about a cat is that it is a macroscopic object. Thus, the Copenhagen interpretation does not consider that the cat is in a state of confusion between living and dead before the box is opened.

In the "many worlds interpretation" quantum mechanics, which does not consider the measurement process to be something special, both states of the cat exist, but decohere, i.e. a process occurs in which a quantum mechanical system interacts with environment and acquires information available in the environment, or otherwise becomes “entangled” with the environment. And when the observer opens the box, he becomes entangled with the cat and from this two states of the observer are formed, corresponding to a living and a dead cat, and these states do not interact with each other. The same mechanism of quantum decoherence is important for “joint” histories. In this interpretation, only a “dead cat” or a “live cat” can be in a “shared story.”

In other words, when the box is opened, the universe splits into two different universes, one in which the observer is looking at a box with a dead cat, and in the other, the observer is looking at a living cat.

The paradox of "Wigner's friend"

Wigner's Friend's Paradox is a complicated experiment of the Schrödinger's cat paradox. Laureate Nobel Prize, American physicist Eugene Wigner introduced the category of “friends”. After completing the experiment, the experimenter opens the box and sees a live cat. The state of the cat at the moment of opening the box goes into the state “the nucleus has not decayed, the cat is alive.” Thus, in the laboratory the cat was recognized as alive. There is a "friend" outside the laboratory. The friend does not yet know whether the cat is alive or dead. The friend recognizes the cat as alive only when the experimenter tells him the outcome of the experiment. But all the other “friends” have not yet recognized the cat as alive, and they will only recognize it when they are told the result of the experiment. Thus, the cat can be recognized as fully alive only when all people in the Universe know the result of the experiment. Until this moment, on the scale of the Big Universe, the cat remains half-alive and half-dead at the same time.

The above is used in practice: in quantum computing and quantum cryptography. A light signal in a superposition of two states is sent through a fiber-optic cable. If attackers connect to the cable somewhere in the middle and make a signal tap there in order to eavesdrop on the transmitted information, then this will collapse the wave function (from the point of view of the Copenhagen interpretation, an observation will be made) and the light will go into one of the states. By conducting statistical tests of light at the receiving end of the cable, it will be possible to detect whether the light is in a superposition of states or has already been observed and transmitted to another point. This makes it possible to create means of communication that exclude undetectable signal interception and eavesdropping.

The experiment (which can, in principle, be performed, although working quantum cryptography systems capable of transmitting large amounts of information have not yet been created) also shows that “observation” in the Copenhagen interpretation has nothing to do with the consciousness of the observer, since in this case the change in statistics by the end of the cable leads to a completely inanimate branch of the wire.

And in quantum computing, the Schrödinger cat state is a special entangled state of qubits in which they are all in the same superposition of all zeros or ones.

("Qubit" is the smallest element for storing information in a quantum computer. It admits two eigenstates, but it can also be in their superposition. Whenever the state of a qubit is measured, it randomly transitions to one of its own states.)

In reality! Little brother of "Schrodinger's cat"

It's been 75 years since Schrödinger's cat appeared, but still some of the consequences of quantum physics seem at odds with our everyday ideas about matter and its properties. According to the laws of quantum mechanics, it should be possible to create a “cat” state in which it is both alive and dead, i.e. will be in a state of quantum superposition of two states. However, in practice, the creation of a quantum superposition of such a large number of atoms has not yet been possible. The difficulty is that the more atoms there are in a superposition, the less stable this state is, since external influences tend to destroy it.

To physicists from the University of Vienna (publication in the journal Nature Communications", 2011) for the first time in the world it was possible to demonstrate the quantum behavior of an organic molecule consisting of 430 atoms and in a state of quantum superposition. The molecule obtained by the experimenters looks more like an octopus. The size of the molecules is about 60 angstroms, and the de Broglie wavelength for the molecule was only 1 picometer. This “molecular octopus” was able to demonstrate the properties inherent in Schrödinger’s cat.

Quantum suicide

Quantum suicide is a thought experiment in quantum mechanics that was proposed independently by G. Moravec and B. Marshall, and was expanded in 1998 by cosmologist Max Tegmark. This thought experiment, a modification of the Schrödinger's cat thought experiment, clearly shows the difference between two interpretations of quantum mechanics: the Copenhagen interpretation and the Everett many-worlds interpretation.

The experiment is actually an experiment with Schrödinger's cat from the cat's point of view.

In the proposed experiment, a gun is pointed at the participant, which fires or does not fire depending on the decay of some radioactive atom. There is a 50% chance that the gun will go off and the participant will die. If the Copenhagen interpretation is correct, then the gun will eventually go off and the participant will die.
If Everett’s many-worlds interpretation is correct, then as a result of each experiment conducted, the universe splits into two universes, in one of which the participant remains alive, and in the other dies. In worlds where a participant dies, he ceases to exist. In contrast, from the perspective of the non-dead participant, the experiment will continue without causing the participant to disappear. This happens because in any branch the participant is able to observe the result of the experiment only in the world in which he survives. And if the many-worlds interpretation is correct, then the participant may notice that he will never die during the experiment.

The participant will never be able to talk about these results, since from the point of view of an outside observer, the probability of the outcome of the experiment will be the same in both the many-worlds and the Copenhagen interpretations.

Quantum immortality

Quantum immortality is a thought experiment that stems from the quantum suicide thought experiment and states that, according to the many-worlds interpretation of quantum mechanics, beings that have the capacity for self-awareness are immortal.

Let's imagine that a participant in an experiment detonates a nuclear bomb near him. In almost all parallel Universes, a nuclear explosion will destroy the participant. But despite this, there must be a small number of alternative Universes in which the participant somehow survives (that is, Universes in which a potential rescue scenario is possible). The idea of quantum immortality is that the participant remains alive, and thereby is able to perceive the surrounding reality, in at least one of the Universes in the set, even if the number of such universes is extremely small compared to the number of all possible Universes. Thus, over time, the participant will discover that he can live forever. Some parallels to this conclusion can be found in the concept of the anthropic principle.

Another example stems from the idea of quantum suicide. In this thought experiment, the participant points a gun at himself, which may or may not fire depending on the outcome of the decay of some radioactive atom. There is a 50% chance that the gun will go off and the participant will die. If the Copenhagen interpretation is correct, then the gun will eventually go off and the participant will die.

If Everett’s many-worlds interpretation is correct, then as a result of each experiment conducted, the universe splits into two universes, in one of which the participant remains alive, and in the other dies. In worlds where a participant dies, he ceases to exist. On the contrary, from the point of view of the non-dead participant, the experiment will continue without causing the participant to disappear, since after each split of universes he will be able to recognize himself only in those universes where he survived. Thus, if Everett's many-worlds interpretation is correct, then the participant may notice that he will never die in the experiment, thereby "proving" his immortality, at least from his point of view.

Proponents of quantum immortality point out that this theory does not contradict any known laws of physics (this position is far from unanimously accepted in the scientific world). In their reasoning, they rely on the following two controversial assumptions:
- Everett’s many-worlds interpretation is correct, not the Copenhagen interpretation, since the latter denies the existence of parallel universes;
- all possible scenarios in which a participant may die during the experiment contain at least a small subset of scenarios in which the participant remains alive.

A possible argument against the theory of quantum immortality is that the second assumption does not necessarily follow from Everett's many-worlds interpretation, and it may conflict with the laws of physics, which are believed to apply to all possible realities. The many-worlds interpretation of quantum physics does not necessarily imply that “anything is possible.” It only indicates that at a certain point in time the universe can be divided into a number of others, each of which will correspond to one of the many possible outcomes. For example, the second law of thermodynamics is believed to apply to all probable universes. This means that, theoretically, the existence of this law prevents the formation of parallel universes where it would be violated. The consequence of this may be the achievement, from the point of view of the experimenter, of a state of reality where his further survival becomes impossible, since this would require a violation of the law of physics, which, according to the previously stated assumption, is valid for all possible realities.

For example, in an explosion nuclear bomb described above, it is quite difficult to describe a plausible scenario that does not violate basic biological principles in which the participant will survive. Living cells simply cannot exist at the temperatures reached in the center nuclear explosion. In order for the theory of quantum immortality to remain valid, it is necessary that either a misfire occurs (and thereby avoid a nuclear explosion), or some event occurs that is based on as yet undiscovered or unproven laws of physics. Another argument against the theory under discussion can be the presence in all creatures of natural biological death, which cannot be avoided in any of the parallel Universes (at least in at this stage development of science)

On the other hand, the second law of thermodynamics is a statistical law, and nothing is contradicted by the occurrence of fluctuations (for example, the appearance of a region with conditions suitable for the life of an observer in a universe that has generally reached a state of thermal death; or, in principle, the possible movement of all particles resulting from nuclear explosion, in such a way that each of them will fly past the observer), although such a fluctuation will occur only in an extremely small part of all possible outcomes. The argument regarding the inevitability of biological death can also be refuted on the basis of probabilistic considerations. For every living organism at a given moment in time, there is a non-zero probability that it will remain alive during the next second. Thus, the probability that he will remain alive for the next billion years is also non-zero (since it is the product large number non-zero factors), although very small.

What is problematic about the idea of quantum immortality is that according to it, a self-aware being will be “forced” to experience extremely unlikely events that will arise in situations in which the participant would seem to die. Even though in many parallel universes the participant dies, the few universes that the participant is able to subjectively perceive will develop in an extremely unlikely scenario. This, in turn, may in some way cause a violation of the principle of causality, the nature of which in quantum physics is not yet clear enough.

Although the idea of quantum immortality stems largely from the “quantum suicide” experiment, Tegmark argues that under any normal conditions, every thinking being before death goes through a stage (from a few seconds to several years) of decreasing level of self-awareness, which has nothing to do with quantum mechanics. and the participant has no possibility of continued existence by moving from one world to another, which gives him the opportunity to survive.

Here, a self-aware rational observer continues to remain in, so to speak, a “healthy body” only in a relatively small number of possible states in which he retains self-consciousness. The possibility that the observer, while retaining consciousness, will remain crippled is much greater than if he remains unharmed. Any system (including a living organism) has much more opportunities to function incorrectly than to remain in ideal shape. Boltzmann's ergodic hypothesis requires that the immortal observer will sooner or later go through all states compatible with the preservation of consciousness, including those in which he will feel unbearable suffering - and there will be significantly more such states than states of optimal functioning of the organism. Thus, as philosopher David Lewis suggests, we should hope that the many-worlds interpretation is wrong.

Surely you have heard more than once that there is such a phenomenon as “Schrödinger’s Cat”. But if you are not a physicist, then most likely you have only a vague idea of what kind of cat this is and why it is needed.
“Schrödinger's Cat” is the name of the famous thought experiment of the famous Austrian theoretical physicist Erwin Schrödinger, who is also a Nobel Prize winner. With the help of this fictitious experiment, the scientist wanted to show the incompleteness of quantum mechanics in the transition from subatomic systems to macroscopic systems.
This article attempts to explain in simple words the essence of Schrödinger's theory about the cat and quantum mechanics, so that it is accessible to a person who does not have a higher technical education. The article will also present various interpretations of the experiment, including those from the TV series “The Big Bang Theory.”
Content:
1. Description of the experiment
2. Explanation in simple words
3. Video from The Big Bang Theory
4. Reviews and comments
Description of the experiment
The original article by Erwin Schrödinger was published in 1935. In it, the experiment was described using the technique of comparison or even personification:

You can also construct cases in which there is quite a burlesque. Let some cat be locked in steel chamber along with the following diabolical machine (which should be regardless of the cat's intervention): inside the Geiger counter there is a tiny amount of radioactive substance, so small that only one atom can decay within an hour, but with the same probability it may not; if this happens, the reading tube is discharged and the relay is activated, releasing the hammer, which breaks the flask with hydrocyanic acid.
If we leave this entire system to itself for an hour, then we can say that the cat will be alive after this time, as long as the atom does not disintegrate. The very first disintegration of the atom would poison the cat. The psi-function of the system as a whole will express this by mixing or smearing a living and a dead cat (pardon the expression) in equal parts. It is typical in such cases that the uncertainty initially limited atomic world, is converted into macroscopic uncertainty, which can be eliminated by direct observation. This prevents us from naively accepting the “blur model” as reflecting reality. This in itself does not mean anything unclear or contradictory. There's a difference between a blurry or out-of-focus photo and a photo of clouds or fog.
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In other words:
1. There is a box and a cat. The box contains a mechanism containing a radioactive atomic nucleus and a container of poisonous gas. The experimental parameters were selected so that the probability of nuclear decay in 1 hour is 50%. If the nucleus disintegrates, a container of gas opens and the cat dies. If the nucleus does not decay, the cat remains alive and well.
2. We close the cat in a box, wait an hour and ask ourselves: is the cat alive or dead?
3. Quantum mechanics seems to tell us that the atomic nucleus (and therefore the cat) is in all possible states simultaneously (see quantum superposition). Before we open the box, the cat-core system is in the state “the nucleus has decayed, the cat is dead” with a probability of 50% and in the state “the nucleus has not decayed, the cat is alive” with a probability of 50%. It turns out that the cat sitting in the box is both alive and dead at the same time.
4. According to the modern Copenhagen interpretation, the cat is alive/dead without any intermediate states. And the choice of the decay state of the nucleus occurs not at the moment of opening the box, but even when the nucleus enters the detector. Because the reduction of the wave function of the “cat-detector-nucleus” system is not associated with the human observer of the box, but is associated with the detector-observer of the nucleus.

Explanation in simple words
According to quantum mechanics, if no observation is made of the nucleus of an atom, then its state is described by a mixture of two states - a decayed nucleus and an undecayed nucleus, therefore, a cat sitting in a box and personifying the nucleus of an atom is both alive and dead at the same time. If the box is opened, then the experimenter can see only one specific state - “the nucleus has decayed, the cat is dead” or “the nucleus has not decayed, the cat is alive.”
The essence in human language: Schrödinger's experiment showed that, from the point of view of quantum mechanics, the cat is both alive and dead, which cannot be. Therefore, quantum mechanics has significant flaws.
The question is: when does a system cease to exist as a mixture of two states and choose one specific one? The purpose of the experiment is to show that quantum mechanics is incomplete without some rules that indicate under what conditions the wave function collapses and the cat either becomes dead or remains alive but is no longer a mixture of both. Since it is clear that a cat must be either alive or dead (there is no state intermediate between life and death), this will be similar for the atomic nucleus. It must be either decayed or undecayed (Wikipedia).
Video from The Big Bang Theory
Another more recent interpretation of Schrödinger's thought experiment is a story that Sheldon Cooper, the hero of the Big Bang Theory, told his less educated neighbor Penny. The point of Sheldon's story is that the concept of Schrödinger's cat can be applied to human relationships. In order to understand what is happening between a man and a woman, what kind of relationship is between them: good or bad, you just need to open the box. Until then, the relationship is both good and bad.
Below is a video clip of this Big Bang Theory exchange between Sheldon and Penia.
Did the cat remain alive as a result of the experiment?
For those who didn’t read the article carefully, but are still worried about the cat, good news: don’t worry, according to our data, as a result of a thought experiment by a crazy Austrian physicist
NO CAT WAS HURT

As Heisenberg explained to us, due to the uncertainty principle, the description of objects in the quantum microworld is of a different nature than the usual description of objects in the Newtonian macroworld. Instead of spatial coordinates and speed, which we are used to describing mechanical movement, for example, a ball along billiard table, in quantum mechanics, objects are described by the so-called wave function. The crest of the “wave” corresponds to the maximum probability of finding a particle in space at the moment of measurement. The movement of such a wave is described by the Schrödinger equation, which tells us how the state of a quantum system changes over time.

Now about the cat. Everyone knows that cats love to hide in boxes (). Erwin Schrödinger was also in the know. Moreover, with purely Nordic fanaticism, he used this feature in a famous thought experiment. The gist of it was that there was a cat locked in a box with an infernal machine. The machine is connected through a relay to a quantum system, for example, a radioactively decaying substance. The probability of decay is known and is 50%. The infernal machine is triggered when the quantum state of the system changes (decay occurs) and the cat dies completely. If you leave the “Cat-box-hellish machine-quanta” system to itself for one hour and remember that the state of a quantum system is described in terms of probability, then it becomes clear that it will probably not be possible to find out whether the cat is alive or not at a given moment in time, just as it will not be possible to accurately predict the fall of a coin on heads or tails in advance. The paradox is very simple: the wave function that describes a quantum system mixes the two states of a cat - it is alive and dead at the same time, just as a bound electron can be located with equal probability in any place in space equidistant from the atomic nucleus. If we don't open the box, we don't know exactly how the cat is doing. Without making observations (read measurements) of an atomic nucleus, we can describe its state only by superposition (mixing) of two states: a decayed and undecayed nucleus. A cat in nuclear addiction is both alive and dead at the same time. The question is: when does a system cease to exist as a mixture of two states and choose one specific one?

The Copenhagen interpretation of the experiment tells us that the system ceases to be a mixture of states and chooses one of them at the moment when an observation occurs, which is also a measurement (the box opens). That is, the very fact of measurement changes physical reality, leading to the collapse of the wave function (the cat either becomes dead or remains alive, but ceases to be a mixture of both)! Think about it, the experiment and the measurements that accompany it change the reality around us. Personally, this fact bothers my brain much more than alcohol. The well-known Steve Hawking also has a hard time experiencing this paradox, repeating that when he hears about Schrödinger’s cat, his hand reaches out to the Browning. The severity of the reaction of the outstanding theoretical physicist is due to the fact that, in his opinion, the role of the observer in the collapse of the wave function (its collapse into one of two probabilistic) states is greatly exaggerated.

Of course, when Professor Erwin conceived his cat-mockery back in 1935, it was an ingenious way to show the imperfection of quantum mechanics. In fact, a cat cannot be alive and dead at the same time. As a result of one of the interpretations of the experiment, it became obvious that there was a contradiction between the laws of the macro-world (for example, the second law of thermodynamics - the cat is either alive or dead) and the micro-world (the cat is alive and dead at the same time).

Another more recent interpretation of Schrödinger's thought experiment is a story that Sheldon Cooper, the hero of the Big Bang Theory, told his less educated neighbor Penny. The point of Sheldon's story is that the concept of Schrödinger's cat can be applied to human relationships. In order to understand what is happening between a man and a woman, what kind of relationship is between them: good or bad, you just need to open the box. Until then, the relationship is both good and bad.